The present invention relates to releasable connectors, and more particularly to a device for releasably connecting the machine draw rod on a production lathe to the chuck draw rod of a power actuated chuck.
Machine lathes are used for the production of varying sizes of components which are normally symmetrical about their axis of rotation. The main cutting motion is made by rotating a workpiece about an axis and the feed motion is made by a cutting tool which tracks longitudinally and radially alongside the rotating workpiece. Chucks having controllable, radially displacable jaws are frequently employed to hold the workpiece. The chucks in turn are attached to a spindle which is rotated by the lathe to produce the rotation of the workpiece.
On production lathes, power actuated chucks are generally used. The gripping jaws on power actuated chucks are actuated in response to the longitudinal movement of a chuck draw rod centrally located within the chuck. The chuck draw rod is in turn connected to a machine draw rod which longitudinally extends within the spindle and which can be controllabiy reciprocated by the lathe operator. The chuck draw rod is typically connected to the machine draw rod by a bolt or draw screw which is threaded axially through the chuck draw rod and received in a tapped hole extending into a forward end of the machine draw rod.
In most production operations, the chuck is constantly removed and exchanged with other chucks or chucking fixtures to provide versatility for a wide range of part sizes to be machined. A common drawback of the bolted connection between the machine draw rod and the chuck draw rod is that the screwing and unscrewing of the bolt causes the internal threads of the machine draw rod to wear or become damaged. This necessitates retapping or replacement of the draw rod which is a time consuming process. A related drawback is that the rotation of the draw screw is a time consuming process and reduces the efficiency of the machining operation.
It is therefore an object of the present invention to provide an apparatus for removably connecting the machine draw rod to the chuck draw rod in a machine lathe without requiring the use of a threaded connection device which can be damaged during replacement of the chuck.
A further object of the present invention is to provide an apparatus which allows a chuck for a machine lathe to be removed and/or installed very quickly. A related object is to provide such an apparatus which can withstand the high push/pull forces generated and applied to the draw rod when chucking a part.